For other things with a longer history, there might be more defined periods of vintage. I knew a doll collector who said dolls had to be 50 years old to be vintage. For furniture, 60s stuff might be called "late vintage." I don't really know about other items. Since
Coach hasn't been making purses that long, there aren't categories, but in my mind, I think there are 3 divisions: bags made between 1989 and 1996, bags with NYC creeds, and pre-creed bags, including Bonnie Cashins.
Many sellers don't know how to read creeds. Maybe they think vintage is another word for used. Others think they will get more views by using the word "vintage" in their listings. Some buyers don't care if a bag is officially vintage but want an all leather bag, like a Willis. It is difficult to find these without searching for vintage. I agree, classic is the word they should be using, but buyers may not know that.